A different and likely larger population that's more likely based on need.

In the event of a disaster, I assert the thing you're sat-solving for is "as many people as possible getting enough of a constrained resource to survive long enough to get out of the disaster condition". In my mind, that's both good and compassionate.

I believe in my case, the population would be people who can make it to the store - unchanged from what it was before the store started limiting quantities.

I'm having a hard time not getting snarky here because, to be honest, you don't seem to be arguing in good faith.

Depends on the outcome and how you measure efficiency.

Say there is a water shortage and lots of hoarding resulting in high profits and a couple of deaths.

Is that outcome more efficient than forced rationing resulting in less profit and less death?